diff --git a/README.md b/README.md
new file mode 100644
index 0000000..6cca14f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,95 @@
+# Automatic backup files script
+
+## Prerquisites
+
+* Rsync (included in Debian, Ubuntu, Linux Mint, etc)
+* Sudo or Root access
+* Terminal learn
+
+## Quick start
+
+
+1- If disk on save backup is diferent a instalation disk:
+
+Copy UUID your disk
+
+    sudo blkid
+
+Editing disks mount points file
+
+    sudo nano /etc/fstab
+
+Replace backup external disk UUID and mount point for you configuration
+```
+# /etc/fstab: static file system information.
+#
+# Use 'blkid' to print the universally unique identifier for a
+# device; this may be used with UUID= as a more robust way to name devices
+# that works even if disks are added and removed. See fstab(5).
+#
+# systemd generates mount units based on this file, see systemd.mount(5).
+# Please run 'systemctl daemon-reload' after making changes here.
+#
+# <file system> <mount point>   <type>  <options>       <dump>  <pass>
+
+# Others discks
+UUID=  /boot/efi       vfat    umask=0077      0       1
+
+# backup external disk
+UUID=645648-kadfvadfb86teyn1sd3  /backup-disk    ext4    defaults        0       0
+```
+
+1- Modify custom service:
+
+* Default backup run on 1 hour (RestartSec=3600)
+* Default bash script path is "/home/backup-files.sh" (ExecStart=/to/bash/file)
+
+```
+[Unit]
+Description=Automatic backup files
+After=network.target
+
+[Service]
+Type=simple
+User=root
+ExecStart=/home/backup-files.sh
+Restart=always
+RestartSec=3600
+
+[Install]
+WantedBy=multi-user.target
+```
+
+2- Copy service into path /etc/systemd/system/
+
+    sudo cp backup-files.service /etc/systemd/system/
+
+    sudo systemctl dameon-reload
+
+    sudo systemctl enable backup-files.service
+
+
+3- Modify script
+
+```
+# Paths
+external_disk=true // Default backup saved on external disk
+backup_path="/backup-disk" //Disk backup mount point
+origins=("/home/user1/files" "/home/user2/files/documents") // Origins files array
+destinations=("$backup_path/backup-user1" "$backup_path/backup-user2") // Destination backups
+```
+
+4- Copy script into ExecStart= path defined in .service
+
+    sudo cp backup-files.sh /home/
+
+
+5- Test script commands
+
+    sudo bash /home/backup-files.sh
+
+6- If before Test not return never error, then start sevice
+
+    sudo systemctl start backup-files.service
+
+    sudo systemctl status backup-files.service
diff --git a/backup-files.sh b/backup-files.sh
index 72ea752..6f406a7 100644
--- a/backup-files.sh
+++ b/backup-files.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
 
 # Paths
+external_disk=true
 backup_path="/backup-disk"
 origins=("/home/user1/files" "/home/user2/files/documents")
 destinations=("$backup_path/backup-user1" "$backup_path/backup-user2")
@@ -16,17 +17,21 @@ perform_backup() {
         return 1
     fi
 
-    # The mount point disk not exists
-    if [ ! -d "$backup_path" ]; then
-        mkdir -p "$backup_path"
-        echo "Mount point disk created"
-    fi
+    if [ external_disk ]; then
 
-    # The disk not mount
-    if ! mountpoint -q "$backup_path"; then
-        echo "Mounting disk..."
-        mount "$backup_path"
+        # The mount point disk not exists
+        if [ ! -d "$backup_path" ]; then
+            mkdir -p "$backup_path"
+            echo "Mount point disk created"
+        fi
+
+        # The disk not mount
+        if ! mountpoint -q "$backup_path"; then
+            echo "Mounting disk..."
+            mount "$backup_path"
+        fi
     fi
+    
 
     # The destination folder not exists
     if [ ! -d "$destination" ]; then
@@ -53,8 +58,11 @@ for (( i=0; i<${#origins[@]}; i++ )); do
     perform_backup "${origins[i]}" "${destinations[i]}"
 done
 
-# Umount disk
-if mountpoint -q "$backup_path"; then
-    echo "Umounting disk..."
-    umount "$backup_path"
+
+if [ external_disk ]; then
+    # Umount disk
+    if mountpoint -q "$backup_path"; then
+        echo "Umounting disk..."
+        umount "$backup_path"
+    fi
 fi